Table 6 Summarizes the most common delivery approaches that can be used for both in vivo and in vitro CRISPR/Cas system delivery
From: Targeting miRNA by CRISPR/Cas in cancer: advantages and challenges
Delivery methods | Carrying capacity | Toxicity | Biosafety level | Advantages | Challenges | Strategies | References |
|---|---|---|---|---|---|---|---|
Adenovirus | 38Â kb | High | BSL-2 | The host genome disruption risk is low Having trouble transducing certain cell types | High immunogenicity | Targeting immune privilege orangs | |
AAV in vitro | 4.7Â kb | Very low | BSL-1 | Animal models with long-term transgenic expression AAV has not been linked to any diseases in humans Very low immunogenicity | Limited size capacity Preexisting immunity to natural serotypes Exposes constantly for a long time after injection Hepatotoxicity | Splicing the Cas protein into two vector Targeting infant and immune privilege organs Using anti-Cas proteins | [88] |
Retrovirus | 8 kb | Low | BSL-2+  | Ability to transform their single-stranded RNA genome into a double stranded DNA molecule Ability to stably integrate into the target cell genome | – | – | [119] |
Lentiviral vector | 8 kb | Moderate | BSL-2+  | Large genetic capacity Ability to transduce both dividing and non-dividing cells | De novo protein expression may cause immunological responses that result in the removal of transduced cells and the production of antibodies that block the action of released factors | Tacrolimus, cyclophosphamide, and cyclosporine can stop the production and release of cytokines as well as the activation and expansion of T cells | [78] |
Baculovirus | 38 kb | Very low | BSL-1 | Flexible enough to contain many genes or big inserts By infecting insect cells, recombinant baculoviruses can easily be created and yield high titers | – | – | |
Electroporation | 15 kb | Very low | BSL-2 | Takes less time and cost Used in in vivo, in vitro, and ex vivo research | Limited experiences in vivo | – | |
Microinjection | No size limitation | – | BSL-1 | Successful approach to inject macromolecules into embryos Guaranty of delivery to the targeted cell | Time consuming Require skill and facilities Performed generally in vitro | A high level of sophistication and physical skills are needed to reduce cell damage | |
Inorganic compound-based nanoparticle | – | Very low | BSL-1 | Non immunogenic Low cytotoxicity High packaging capacity | Delivery efficiency is low | – | [222] |
Polymeric delivery system | – | Very low | BSL-1 | Non immunogenic Transient expression High packaging capacity | Cytotoxicity In vivo efficacy is low | – | [222] |